Oil well pumpjacks which are connected by a string of rods to a submerged reciprocating pump place a cyclic load on the motor or prime mover which drives the system. The power required to maintain a continuous operation in which the weight of the loaded system pump requires considerably more power during some parts of the cycle than other parts of the cycle and results in a wide fluctuation of power consumed. The resulting increasing energy consumed can be substantial and the wear on the drive motor excessive.
It is known to vary the power output from a constance speed electric motor by mounting a variable speed pulley on the motor output shaft. Pfleger U.S. Pat. No. 2,211,986 issued Aug. 20, 1940, for example, discloses a variable speed electric motor drive having a manually adjustable pulley for varying the effective pulley diameter. The drive motor is mounted on a pivotal base or on a spring-loaded slidable base to maintain the drive belt in a tightened condition.
Hallinan U.S. Pat. No. 2,369,044 issued Feb. 6, 1945 discloses a heating system having another embodiment of an automatic, belt-tightening assembly in which the change in placement of a pivotally mounted electric drive motor relative to a stationary blower controlled, for example, by a thermostatically-controlled bellows, is compensated by a spring-loaded variable-diameter pulley on the drive motor to maintain a constant belt tension. A desired blower speed can be obtained whereby the blower speeds up when the air temperature increases and slows down when the air temperature decreases.
Morton et. al. U.S. Pat. No. 2,479,764 issued Aug. 23, 1949, discloses a transmission governor for use with an electric motor wherein spring-loaded variable diameter pulleys are used in combination with governors to maintain a constant output speed with controlled belt tension.
Heyer U.S. Pat. No. 2,189,288 issued Feb. 6, 1940 discloses another embodiment of a variable speed transmission having one or more variable-diameter pulleys in which the drive motor is manually pivotable to maintain a desired belt tension.
None of the above patents discloses a power regulating apparatus for controlling the power required for a cyclic load wherein which the load demands transmitted to a constant speed motor are maintained substantially constant.
It is a principal object of the present invention, therefore, to provide a power regulating torque control apparatus for use in combination with a constant speed motor for equalizing power requirements of a cyclic load on the said motor.
It is another object of the present invention to provide a relatively simple and positively acting apparatus particularly suited for use with oil well pumpjacks.